CN111683728A

CN111683728A - Multipurpose composite gas filter

Info

Publication number: CN111683728A
Application number: CN201980011679.5A
Authority: CN
Inventors: H·C·克纳普; J·S·博诺莫尔利; H·S·鲁塞尔; C·默辛格; 塞尔坦·奥斯特加德·萨尔塔·克里斯托弗森; M·约翰逊
Original assignee: Airlabs BV
Current assignee: Breath Ltd
Priority date: 2018-02-05
Filing date: 2019-02-05
Publication date: 2020-09-18
Also published as: WO2019149952A1; EP3749435A1; EP3520880A1; US20210229025A1; JP2021513429A

Abstract

The present invention relates to a filter for removing a plurality of target molecules from a gas stream, the filter comprising a three-dimensional porous support, permeable to the gas stream, a first plurality of active particles for removing first undesired molecules, and a second plurality of active particles for removing second undesired molecules; wherein the first plurality of active particles is different from the second plurality of active particles, and wherein the first and second plurality of active particles are immobilized on or by a solid support. The present invention is a composite filter for removing components from an air stream by capture or conversion that utilizes a composite filter that includes multiple distinct active areas having various chemical properties and different chemical compositions within the same filter.

Description

Multipurpose composite gas filter

Technical Field

The present invention relates to a composite filter and use of the composite filter in an air conditioner or an air cleaner. Furthermore, the invention relates to an air cleaning device comprising the composite filter. Furthermore, the invention relates to a motor vehicle comprising an air-conditioning device, an air-cleaning device or both an air-cleaning device and an air-conditioning device, wherein any of these devices comprises a composite filter. The invention also relates to a method of removing polluting elements from ambient air, the method comprising conveying the ambient air through a composite filter. The present invention is a composite filter for removing components from an air stream by capture or conversion that utilizes a composite filter that includes multiple distinct active areas having various chemical properties and different chemical compositions within the same composite filter.

Background

Air pollution is harmful to health; according to the world health organization, air pollution is the largest environmental threat, being more deadly annually than traffic accidents, diabetes and aids combined. World banks report that the combined effect of air pollution is a significant outflow of major economies.

Air pollution includes many gaseous and condensed phase materials. Focusing on its influence on human health, some main components of air pollution are Particulate Matter (PM) and ozone (O)₃) Nitrogen Oxide (NO), nitrogen dioxide (NO)₂) Volatile Organic Compounds (VOCs) (such as formaldehyde (CH)₂O)), and carbon monoxide (CO). As a common example, diesel engines may be fine particulate matter (diesel soot) and nitrogen monoxide and dioxide (NO and NO) due to their operating properties₂Collectively labeled "NOx") from a significant source. Air pollution varies significantly with location and time; the source may be a primary emission or pollution formed in the atmospheric environment. Above the elevated background concentration, there may be local sources. Local sources may include diesel vehicles, livestock, humans heating their homes with wood or coal fired furnaces, sand storms, industrial or agricultural combustion, and the like. Furthermore, there may be quite local sources of air pollution, such as cigarette smoke. Air pollution is also found in vehicles, for example when the vehicle is left in the sun, the temperature can be extremely high, resulting in the emission of many undesirable compounds from the interior of the vehicle.

Air pollution poses a considerable threat to human health. As an example, the uk expects 40000 early times per year to be associated with exposure to poor quality air, and the production costs for uk business, society and health services accumulate over 200 billion pounds per year.

A large proportion of the early decay can be attributed to nitrogen dioxide, which is generated primarily as a result of the combustion process, with the exhaust gases of vehicles being the predominant NO in urban environments₂And (4) source. NO₂Adverse effects on human health are well documented and include airway inflammation, impaired lung function, exacerbation of pre-existing asthma, and increased sensitivity to respiratory infections. For NO₂The annual average limit set by the European Union is 40 μ g/m³And the average concentration limit as the average value in hours is 200. mu.g/m³。

In addition, there are many odours, such as industrial and agricultural emissions. Food production, plastic manufacturing, refineries, painting and gluing produce a wide range of Volatile Organic Compounds (VOCs) and particulate matter. Livestock production can produce strong odors including ammonia and hydrogen sulfide. The effects of these compounds on humans can include inflammation, headache, asthma, and other health effects. The odour itself is usually controllable.

Persons, street pedestrians, etc. in open or semi-open spaces such as in street valleys (with stores, restaurants, coffee shops, clubs, street valleys), transportation and terminal stations (including train, bus and airplane terminal stations), airports, malls, are exposed to contaminated air from traffic, cooking, industrial and other sources.

Preventing human exposure to air pollution is complicated. It may involve converting an entire vehicle to a low emission vehicle, which may be impractical due to the time and cost required. Preventing pollution at its source is a preferred solution, but many sources of pollution (wildfires, dust, transportation, heating, etc.) are difficult to control, and there is a need for air cleaning apparatus to protect persons and businesses in a particular location before source control has been universally implemented for many sources. The air purifier removes contaminants, such as O₃、VOC、NO₂And PM 2.5. These air purifiers generally include a fan, one or more filters, and a case for accommodating the fan and the filters. Many filtration methods are known, such as mechanical filtration, adsorption, gas phase advanced oxidation and electrostatic filtration, and different methods are suitable for different removal tasks.

Air filtration involves the removal of one or more components from a gas stream. This can be achieved by: adsorption or absorption, physisorption or chemisorption, liquid scrubbers, or, in the case of aerosol particles, impact and interception with fibers or electrostatic filters. The active media may include large surface areas for physisorption (examples include activated carbon, graphene, metal organic frameworks), catalysts, photocatalysts, photo-thermal catalysts, reactive substrates (biofiltration, chemical reagents), and homogeneously mixed materials (e.g., activated carbon impregnated with chemical reagents). In many cases, the air stream will undergo multiple treatment stages, for example, a catalyst followed by a chemical "managed" filter, or an acidic scrubber followed by a basic scrubber. It is important that the filter will be able to handle large volumes of air in small volumes without requiring large amounts of energy, which means that it should not impede the air flow. For different types of contamination, it is difficult to combine multiple filtration functions in a small, efficient filter.

Disclosure of Invention

Materials including adsorbents (e.g., activated carbon, Metal Organic Frameworks (MOFs) (e.g., aluminum fumarate, HKUST-1, FeBTC, ZIF-8, or Ni-MOF-74) and other graphene/carbon-based materials), catalysts (e.g., gold nanoclusters, metal oxides), and photocatalysts (e.g., titanium dioxide, mixed metal oxides, composite metal oxides/graphene) remove contaminants in contact therewith. The performance of such systems can be enhanced by doping the surface, however, many combinations are not mutually compatible. For example, each surface that is in contact with the atmospheric environment is covered with a layer of water (ranging from a single molecule thickness at very low relative humidity to a layer that is chemically similar to bulk water at high humidity). To interact with the surface, the contaminants must penetrate the layer. The affinity of many contaminants for water changes dramatically with pH. Some contaminants are acid gases (e.g., hydrogen sulfide, nitric acid, sulfuric acid, nitrous acid, hydrochloric acid, formic acid, acetic acid), and alkaline substrates will be better at harvesting contaminants that interact with the surface. Other contaminants are alkaline gases (e.g., ammonia, amines, proton acceptors/electron donors), and an acidic substrate will enhance the performance of the adsorbent, catalyst, or photocatalyst. In this example, there is a problem in that one material cannot have both acidity and alkalinity because the acid and the alkali neutralize each other.

The present invention relates to a composite filter for reducing or removing, for example, contamination, having a composite macro-morphology in the sense that there are multiple chemical domains with different filtering capacities. One example would be to utilize a mixture of activated carbon beads having different chemistries that are incompatible within the same bead. For example, acid and base impregnation, or by mixing some beads with embedded catalysts, etc., the composite filters different sets of targeted pollutants or gaseous components. Certain advantages are obtained by mixing beads with different chemical domains to form a composite filter, rather than mixing the chemicals in an impregnated manner as used on all beads. For example, the chemicals used may be incompatible with each other, or they may inhibit the activity of a particular ingredient. Composite filters comprising a mixture of multiple domains (e.g., in the form of different types of treated and/or untreated activated carbon beads) can be optimized to target specific contaminating mixtures. Furthermore, impregnation itself may inhibit adsorption and/or reduce the available surface area. In addition, it may be advantageous to capture semi-volatile contaminants within the composite filter in one bead so that they can be re-released and captured in a nearby reactive bead, resulting in a composite filter with high capacity and self-regenerable. The composite filters of the present invention may comprise a support structure, an adsorbent substrate (such as activated carbon) and a chemically active material (reactive dopants and/or (photo) catalysts); the present invention relates to a composite filter morphology with multiple chemical domains resulting in improved performance.

The present invention relates to a composite filter for removing a plurality of target molecules from a gas stream, the composite filter comprising a three-dimensional porous support, the three-dimensional porous support being permeable to the gas stream, a first plurality of active particles for removing a first target molecule, and a second plurality of active particles for removing a second target molecule; wherein the first plurality of active particles is different from the second plurality of active particles, and wherein the first and second plurality of active particles are immobilized on or by a solid support.

In another aspect, the present disclosure is directed to a composite filter for removing a plurality of target molecules from a gas stream, the composite filter comprising a three-dimensional porous support permeable to the gas stream, a first plurality of active particles for removing the first target molecules, and a second plurality of active particles for removing the second target molecules, wherein the first plurality of active particles is different from the second plurality of active particlesAn active particle, wherein the first and second plurality of active particles are immobilized in or by a support, and wherein each of the first and second plurality of active particles is independently selected from the group consisting of an activated carbon particle, an activated carbon particle pretreated/impregnated with a metal, an activated carbon particle pretreated/impregnated with an enzyme, an activated carbon particle pretreated/impregnated with a basic compound, an activated carbon particle pretreated/impregnated with an acidic compound, a Metal Organic Framework (MOF) particle, a catalyst particle, a doped metal oxide particle, 1 wt% Pt/TiO₂Granular, 0.1 wt% Pt/Fe₂O₃Particulate, 3 wt% Pt/MnOx-CeO₂Particles, photocatalytic particles. In one embodiment, the first plurality of active particles is selected from doped metal oxide particles and the second plurality of active particles is selected from impregnated activated carbon particles. In yet another embodiment, the doped metal oxide particles are doped to provide the chemistry of targeting a specific portion of the contaminant, such as gold nanoclusters on modified graphene or other metal nanoclusters, such as silver nanoclusters, e.g. cerium (IV) oxide (CeO)₂) 1 wt% gold on the particles. In yet another embodiment, the first plurality of active particles are selected from metal organic framework particles, such as at least one of aluminum fumarate, HKUST-1, FeBTC, ZIF-8, or Ni-MOF-74, Cu-BTC. In yet another embodiment, the second plurality of active particles are selected from metal organic framework particles, such as at least one of aluminum fumarate, HKUST-1, FeBTC, ZIF-8, or Ni-MOF-74, Cu-BTC.

In one embodiment, the gas is ambient air and the target molecule is a contaminant included in the ambient air.

In another embodiment, the first and/or second plurality of active particles are doped to provide the chemistry of the contaminant targeted to the specific moiety.

In this connection, doped or doped is intended to mean a thin molecular layer that is physically attached or chemically bonded to the surface of the particles in order to render them active, which does not cover the entire surface area. Doping is the intentional addition of additional trace species by any means. The additional trace species may be a catalyst, trace chemical reagent, or the like. Doping can be achieved by impregnation or by coating.

In yet another embodiment, the contaminant is selected from at least one of: volatile organic compounds, municipal pollutants, naturally occurring compounds, traffic emissions, indoor sources (e.g., painted walls, automotive dashboards, degassing of electronic devices), industrial sites (e.g., power plants, paint shops, sewage treatment plants, tunnels, terminal buildings, ports, passenger terminals, petrochemical facilities, material manufacturing, biofuel storage and processing, food production, livestock facilities), construction sites, natural sources (fibers, sandstorms), or occupational air pollution loads (including harmful and harmless concentrations of pollution). Typically, the contaminant is selected from at least one of: ozone, nitrogen oxides, sulfur oxides, formaldehyde, carbon monoxide, ammonia, and hydrogen sulfide.

In yet another embodiment, the porous carrier comprises a third plurality of active particles for removing a third target molecule, wherein the third plurality of active particles is different from the first and second plurality of active particles, and wherein the third plurality of active particles is immobilized in or by a solid carrier.

In yet another embodiment, the porous carrier body comprises a further plurality of active particles for removing a further target molecule, wherein the further plurality of active particles is different from the first, second and third plurality of active particles, and wherein the further plurality of active particles is immobilized in or by a solid carrier. Such another plurality of active particles is defined as the fourth, fifth, sixth, etc., and is a plurality of embodiments of the present invention.

In yet another embodiment, the first, second, optional third, and optional further plurality of active particles are each independently selected from activated carbon particles, activated carbon particles pretreated/impregnated with a metal, activated carbon particles pretreated/impregnated with an enzyme, activated carbon particles pretreated/impregnated with a basic compound, activated carbon particles pretreated/impregnated with an acidic compound, Metal Organic Framework (MOF) particles such as aluminum fumarate, HKUST-1 (copper benzene-1, 3, 5-tricarboxylate), FeBTC (iron 1,3, 5-benzene tricarboxylate), ZIF-8 (zinc 2-methylimidazole salt), or Ni-MOF-74, catalyst particles such as cerium (r: (r) (r))IV) oxide (CeO)₂) 1 wt% of doped gold nanoclusters on particles), 1 wt% of Pt/TiO₂Granular, 0.1 wt% Pt/Fe₂O₃Particulate, 3 wt% Pt/MnOx-CeO₂Particles, photocatalytic particles; with the proviso that the first, second, optional third and optional further plurality of active particles are selected from different active particles.

In yet another embodiment, the three-dimensional porous support is selected from the group consisting of (i) a foam support body having a reticulated pore structure, (ii) a felt of chemical or biopolymer fibers, (iii) twisted fiber strands, (iv) a flexible knit, (v) a mesh bundle, (vi) a pile of wires, (vii) a pleated paper substrate, (viii) an air-permeable three-dimensional rigid frame (e.g., a metal wire or monofilament), (viii) a brush filter, and (ix) a material designed to impart a reaction surface of minimum flow resistance and maximum accessibility to a flow of gas (such as air).

In yet another embodiment, the first, second, optional third and optional further plurality of active particles have from 100m²G to 7000m²Total surface area in g. Typically, the first, second, optional third and optional further plurality of active particles have a particle size of from 800m²G to 2000m²G, such as from 1000m²G to 1700m²Total surface area in g.

In yet another embodiment, the first, second, optional third and optional further plurality of active particles are secured to the pore structure of the carrier by an adhesive forming an adhesive layer.

In yet another embodiment, the activated carbon particles are selected from activated carbon spheres, activated carbon beads, and/or activated carbon granules.

In yet another embodiment, the first, second, optional third and optional further plurality of active particles have an average particle size in the range of from 0.005m to 3.0mm, such as 0.01mm to 2.0 mm.

In yet another embodiment, the first, second, optional third and optional further plurality of active particles are independently selected from activated carbon particles pretreated with lithium permanganate, calcium acetate, copper dioxide, potassium hydroxide, sodium hydroxide, calcium hydroxide or manganese hydroxide, potassium permanganate, manganese dioxide, copper nitrate, manganese acetate, potassium carbonate or sodium permanganate.

In yet another embodiment, the foam is a polyurethane-based foam, such as a polyester and/or polyether-based foam.

In yet another embodiment, the adhesive layer has a thickness obtainable by coating the foam with the adhesive at least twice (such as 2 to 10 times, typically 4 to 6 times).

In yet another embodiment, the adhesive is selected from hot melt adhesives, such as ethylene vinyl acetate based adhesives; or adhesives based on polystyrene, urethane, liquid resins, polyurethane and/or styrene.

In yet another embodiment, the composite filter exhibits a low pressure drop and a specific space velocity when air or gas is conveyed through the composite filter to remove contaminants from the air or gas, wherein the pressure drop is less than 20Pa and the space velocity is from 5.000h-1 to 180.000 h-1.

In a further aspect, the present invention relates to the use of a composite filter according to any of the above aspects and/or embodiments in an air cleaning device.

In a further aspect, the invention relates to the use of a composite filter according to any of the above aspects and/or embodiments in an air conditioning device.

In yet another aspect, the present disclosure relates to an air cleaning device comprising a composite filter according to any one of the above aspects and/or embodiments.

In yet another aspect, the invention relates to a motor vehicle comprising an air conditioning device, an air cleaning device, or both an air cleaning device and an air conditioning device, wherein any of these devices comprises a composite filter according to any of the above aspects and/or embodiments.

In yet another aspect, the invention relates to a method of removing contaminating molecules from ambient air, the method comprising conveying ambient air through a composite filter according to any of the above aspects and/or embodiments.

Other objects and advantages of the invention will be apparent from the following description and claims.

Detailed Description

Optimal pollution control for a wide range of pollutants can be achieved with composite filters comprising materials with different chemical environments; these chemical domains are not necessarily compatible with each other. One example would be a mixture of acid treated activated carbon beads and base treated activated carbon beads. The beads comprising the mixture may be optimized to target a particular contaminant or a particular contaminant type (acid gas or base gas), or perhaps a catalyst (e.g., for formaldehyde, gold nanoclusters) that targets a particular form of contaminant. Since acid or base treatment can reduce the capacity of the material, and therefore it may be optimal to have some untreated beads that add storage capacity to the composite filter. These beads will trap the contaminants and hold them in the area where the beads are treated, which area treats the contaminants. The performance depth of a wide range of air pollution is gained by blending the beads with different chemical environments.

The present invention relates to a composite filter for removing a plurality of target molecules from a gas stream, the composite filter comprising a three-dimensional porous support, the three-dimensional porous support being permeable to the gas stream, a first plurality of active particles for removing a first target molecule, and a second plurality of active particles for removing a second target molecule; wherein the first plurality of active particles is different from the second plurality of active particles, and wherein the first and second plurality of active particles are immobilized on or by a carrier.

When removing multiple target molecules from a gas, the term "multiple" means at least two different kinds of target molecules, such as ozone, nitrogen oxides, sulfur oxides, formaldehyde, carbon monoxide, and hydrogen sulfide.

As used herein, the term "three-dimensional porous support permeable to gas flow" means a support permeable to gas flow and which is itself a three-dimensional structure or which can be used to form a three-dimensional structure. Examples are a foam carrier body with a reticulated pore structure, a felt of polymer fibers, twisted fiber threads, flexible knits, mesh strands, wire stacks, pleated paper substrates, air permeable three dimensional rigid frames (e.g., metal wires or monofilaments), brush-like composite filters, and materials designed to impart a reactive surface of minimum flow resistance and maximum accessibility to gases.

As used herein, "target molecule" means one or more molecules (including clusters of molecules) that have been determined to be removed from a gas stream, such as ambient air. Based on such a determination, a plurality of active particles are selected and incorporated into the composite filter of the present invention.

As used herein, the term "molecular cluster" is an ensemble between 5 to 105 atoms or molecules that are bonded to each other by van der waals interactions, valence of electron sharing (covalent bonding), or by ionic bonding. The clusters may comprise a mixture of different molecules; one cluster may be predominantly a different organic molecule, while the other cluster is predominantly an acidic or basic molecule.

When the first and second plurality of active particles (or even the third or further plurality of active particles) are fixed to a solid support, this means that such active particles are fixed to the support, such as glued to the support; and when the active particles are held by the carrier, this means that the active particles are held in place by the structure of the carrier.

As used herein, the term "ambient air" is, without limitation, city air, room air, industrial exhaust air, process exhaust air, air in enclosed spaces (in cars, in buses, in trucks, in taxis, etc.), air in semi-enclosed spaces (in bus stations, train stations, parking garages, etc.), air emitted by traffic or ships, air emitted by construction sites, air emitted by biological or natural sources, air found in the earth's atmospheric environment, air that is unable to escape the earth's gravitational forces.

In another embodiment, the first plurality of active particles are doped to provide the chemistry of the contaminant targeted to the specific moiety.

In another embodiment, the second plurality of active particles is doped to provide the chemistry of the contaminant targeted to the specific moiety.

In another embodiment, the first and second plurality of active particles are doped to provide the chemistry of the contaminant targeted to the specific moiety.

In yet another embodiment, the contaminant is selected from at least one of: volatile organic compounds, municipal pollutants, naturally occurring compounds, traffic emissions, indoor sources (e.g., painted walls, car dashboards, degassing of electronic devices), industrial sites (e.g., power plants, paint shops, sewage treatment plants, tunnels, terminal buildings, ports, passenger terminals, petrochemical facilities, material manufacturing, biofuel storage and processing, food production, livestock facilities), construction sites, natural sources (fibers, sandstorms), occupational air pollution loads (including harmful and harmless concentrations of pollution). Typically, the contaminant is selected from at least one of: ozone, nitrogen oxides, sulfur oxides, formaldehyde, carbon monoxide, ammonia, and hydrogen sulfide.

In yet another embodiment, the porous carrier body comprises a further plurality of active particles for removing a further target molecule, wherein the further plurality of active particles is different from the first, second and third plurality of active particles, and wherein the further plurality of active particles is immobilized in or by a solid carrier.

In yet another embodiment, the first, second, optional third and optional further plurality of active particles are each independently selected from the group consisting of activated carbon particles, activated carbon particles pretreated/impregnated with a metal, activated carbon particles pretreated/impregnated with an enzyme, activated carbon particles pretreated/impregnated with a baseActivated carbon particles pretreated/impregnated with acidic compounds, Metal Organic Framework (MOF) particles such as aluminum fumarate, HKUST-1 (copper benzene-1, 3, 5-tricarboxylate), FeBTC (iron 1,3, 5-benzene-tricarboxylate), ZIF-8 (zinc 2-methylimidazole salt), or Ni-MOF-74, catalyst particles such as cerium (IV) oxide (CeO)₂) 1 wt% of doped gold nanoclusters on particles), 1 wt% of Pt/TiO₂Granular, 0.1 wt% Pt/Fe₂O₃Particulate, 3 wt% Pt/MnOx-CeO₂Particles, photocatalytic particles; with the proviso that the first, second, optional third and optional further plurality of active particles are selected from different active particles. In yet another embodiment, there is a first, second, and third plurality of active particles. In yet another embodiment, there is a first, second, third, and fourth plurality of active particles. In yet another embodiment, there is a first, second, third, fourth, and fifth plurality of active particles. In yet another embodiment, there is a first, second, third, fourth, fifth, and sixth plurality of active particles.

In yet another embodiment, the three-dimensional porous support has a pore size of less than 25 Pores Per Inch (PPI). Typically, the pore size is from 5PPI to 20PPI, such as from 8PPI to 12 PPI.

In yet another embodiment, the three-dimensional porous support is selected from the group consisting of (i) a foam support body having a reticulated pore structure, (ii) a felt of polymer fibers, (iii) twisted fiber strands, (iv) a flexible knit, (v) a mesh bundle, (vi) a wire pack, (vii) a pleated paper substrate, (viii) an air-permeable three-dimensional rigid frame (e.g., a metal wire or monofilament), (viii) a brush composite filter, and (ix) a material designed to impart a reactive surface of minimum flow resistance and maximum accessibility to a gas (such as air) stream.

In yet another embodiment, the first plurality of active particles has a particle size of from 500m²G to 3000m²Total surface area in g. In yet another embodiment, the second plurality of active particles has a particle size of from 500m²G to 3000m²Total surface area in g. In yet another embodiment, the third plurality of active particles has a particle size of from 500m²G to 3000m²Total of/gSurface area. In yet another embodiment, the another plurality of active particles has from 500m²G to 3000m²Total surface area in g. When another plurality of active particles is present in the porous carrier, this may mean 4, 5, 6, 7, 8, 9 or 10 different pluralities of active molecules. Typically, the first, second, optional third and optional further plurality of active particles have a particle size of from 800m²G to 2000m²G, such as from 1000m²G to 1700m²Total surface area in g.

As used herein, the term "plurality" means that at least 3 active particles are present in the porous carrier; and typically, when the filter is used in an automobile, for example, there are more than 100 active particles.

In yet another embodiment, the first plurality of active particles is secured to the pore structure of the carrier by an adhesive that forms an adhesive layer.

In yet another embodiment, the second plurality of active particles is secured to the pore structure of the carrier by an adhesive that forms an adhesive layer.

In yet another embodiment, the third plurality of active particles is secured to the pore structure of the carrier by an adhesive that forms an adhesive layer.

In yet another embodiment, another plurality of active particles is secured to the pore structure of the carrier by an adhesive that forms an adhesive layer.

In yet another embodiment, the first plurality of active particles has an average particle size in a range of 0.005mm to 3.0 mm. In yet another embodiment, the second plurality of active particles has an average particle size in a range of 0.005mm to 3.0 mm. In yet another embodiment, the third plurality of active particles has an average particle size in a range of 0.005mm to 3.0 mm. In yet another embodiment, the another plurality of active particles has an average particle size in a range of 0.005mm to 3.0 mm. Typically, the average particle size is in the range of 0.01mm to 2.0 mm.

In yet another embodiment, the first plurality of active particles are selected from activated carbon particles pretreated with lithium permanganate, calcium acetate, copper dioxide, alkaline or alkaline earth hydroxides, potassium permanganate, manganese dioxide, copper nitrate, manganese acetate, potassium carbonate, or sodium permanganate.

In yet another embodiment, the second plurality of active particles are selected from activated carbon particles pretreated with lithium permanganate, calcium acetate, copper dioxide, alkaline or alkaline earth hydroxides, potassium permanganate, manganese dioxide, copper nitrate, manganese acetate, potassium carbonate, or sodium permanganate.

In yet another embodiment, the third plurality of active particles is selected from activated carbon particles pretreated with lithium permanganate, calcium acetate, copper dioxide, alkaline or alkaline earth hydroxides, potassium permanganate, manganese dioxide, copper nitrate, manganese acetate, potassium carbonate, or sodium permanganate.

In yet another embodiment, the another plurality of active particles is selected from activated carbon particles pretreated with lithium permanganate, calcium acetate, copper dioxide, alkaline or alkaline earth hydroxides, potassium permanganate, manganese dioxide, copper nitrate, manganese acetate, potassium carbonate, or sodium permanganate.

In yet another embodiment, the three-dimensional porous support is selected from a foam support body having a reticulated pore structure. Preferably, the foam is a polyurethane based foam, such as a polyester and/or polyether based foam.

In yet another embodiment, the adhesive layer has a thickness obtainable by coating the foam at least twice with the adhesive. Typically, the foam is coated 2 to 10 times, such as 4 to 6 times, with the adhesive.

In yet another embodiment, the adhesive is selected from hot melt adhesives. In yet another embodiment, the adhesive is selected from ethylene vinyl acetate based adhesives.

In yet another embodiment, the adhesive is selected from polystyrene, urethane, liquid resin, polyurethane, and/or styrene based adhesives.

In yet another embodiment, the composite filter exhibits a low pressure drop and a specific space velocity when air or gas is conveyed through the composite filter to remove contaminants from the air or gas, wherein the pressure drop is less than 20Pa and the space velocity is 5.000h^-1To 180.000h^-1。

Each and every embodiment as described in connection with the different aspects is also applicable to the other aspects described above, individually and in combination.

As used herein, the term "air cleaning device" means a unit configured to draw air into the unit; wherein the air is cleaned of contaminants, such as by directing the air through a composite filter of the present invention that removes contaminants or a portion of the contaminants, and then out of the unit, for example, by means of a fan, wind powered device, or the like. Typical configurations of such air cleaning devices are known to the skilled person. The air cleaning device is adapted to receive electric current from, for example, an electric power cable.

As used herein, the term "fine particulate" means particles having a Mean Mass Aerodynamic Diameter (MMAD) of less than 300 nm. The terms "nanoparticles" or "fine particles" are used interchangeably with fine particulate matter.

The present invention will now be described more fully with reference to the accompanying drawings, which show exemplary embodiments of street furniture in which air cleaning apparatus is integrated.

These drawings in no way limit the scope of the invention and are only intended to guide the skilled person in a better understanding of the invention.

Fig. 1 shows a foam carrier body (10), the foam carrier body (10) having a reticulated pore structure composite filter with a different plurality of active particles. A small part of the filter body (10) is enlarged (19) and different active particles (11, 12, 13, 14, 15, 16) are shown. For example, the first active particles (11) may be catalyst beads, or more specifically, gold nanoclusters on cerium (IV) oxide catalyst particles. The second active particles (12) may be activated carbon beads, more specifically activated carbon particles impregnated with potassium permanganate. The third active particles (13) may be alkaline/alkaline activated carbon beads, more specifically activated carbon particles impregnated with potassium hydroxide. The fourth active particles (14) may be acidic activated carbon particles, more specifically activated carbon particles impregnated with nitric acid. The fifth active particle (15) may be an active MOF particle, more specifically, an HKUST-1 particle. The sixth active particles (16) may be activated carbon particles, more specifically, non-impregnated activated carbon particles to keep the surface area as high as possible. The foam walls (18) constitute a porous structure with empty spaces (17) between these foam walls. The active particles may be glued to the surface of the pores.

Fig. 2 shows a felt of a polymer fiber filter (20) with different active particles (24 to 29). A small portion of the filter (20) is enlarged (30) and different active particles (24 to 29) are shown. The different active particles may be selected from the same particles as in fig. 1, such that the active particles (11 to 16) correspond to (24 to 29), respectively. The felt consists of fibres (21) and empty spaces (22). The active particles may be glued to the surface of the fibres.

Fig. 3 shows a spun yarn or strand filter (40) with different active particles (43 to 48). A small portion of the filter (40) is enlarged (42) and different active particles (43 to 48) are shown. The different active particles may be selected from the same particles as in fig. 1, such that the active particles (11 to 16) correspond to (43 to 48), respectively. The thread (40) is composed of fibers (49) which are spun as shown. The active particles may be glued onto the surface of the thread.

Fig. 4 shows a flexible knitted fabric filter (50) with different active particles (53 to 58). A small portion of the filter (50) is enlarged (51) and different active particles (53 to 58) are shown. The different active particles may be selected from the same particles as in fig. 1, such that the active particles (11 to 16) correspond to (53 to 58), respectively. The knitted fabric (50) is composed of fibers (51) and empty spaces (52). The active particles may be glued to the surface of the fabric.

Fig. 5 shows a sponge or mesh bundle filter (79) with different active particles (73 to 78). A small portion of the filter (79) is enlarged (70) and the different active particles (73 to 78) are shown. The different active particles may be selected from the same particles as in fig. 1, such that the active particles (11 to 16) correspond to (73 to 78), respectively. The mesh filter (79) is composed of fibers (71) and empty spaces (72) in the mesh. The active particles may be glued to the surface of the fibres.

Fig. 6 shows a wire stack or bundle made of one wire filter (120) with different active particles (123 to 128). A small portion of the filter (120) is an enlarged view of the wire (122) and shows the different active particles (123 to 128). The different active particles may be selected from the same particles as in fig. 1, such that the active particles (11 to 16) correspond to (123 to 128), respectively. The thread filter (120) is composed of a plurality of threads (129) made in a bundle. The active particles may be glued to the surface of the thread.

Fig. 7 shows a pleated paper or nonwoven substrate filter (90) with different active particles (93 to 98). A small portion of the filter (90) is an enlarged view of the wire (92) and shows the different active particles (93 to 98). The different active particles may be selected from the same particles as in fig. 1, such that the active particles (11 to 16) correspond to (93 to 98), respectively. The substrate filter (90) is composed of a pleated filter substrate (99). The active particles may be glued onto the surface of the creped paper.

Fig. 8 shows a three-dimensional rigid frame filter (100) with different active particles (103 to 108). A small portion of the filter (100) is an enlarged view of the three-dimensional rigid frame (102) and shows the different active particles (103 to 108). The different active particles may be selected from the same particles as in fig. 1, such that the active particles (11 to 16) correspond to (103 to 108), respectively. The frame filter (100) is comprised of a rigid frame (109). The active particles may be glued to the frame.

Fig. 9 shows a feather or brush filter (130) with active particles on brush wires (132). A small portion of the filter (130) is an enlarged view of the brush wire (139) and shows the different active particles (133 to 138). The different active particles may be selected from the same particles as in fig. 1, such that the active particles (11 to 16) correspond to (133 to 138), respectively. The brush filter (130) is composed of a plurality of brush wires (132) to which active particles can be glued.

All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

All headings and sub-headings are used herein for convenience only and should not be construed as limiting the invention in any way.

Any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein; and each separate value is incorporated into the specification as if it were individually recited herein. Unless otherwise stated, all precise numerical values provided herein represent corresponding approximate numerical values (e.g., all exemplary precise numerical values provided with respect to a particular factor or measurement may be considered to also provide a corresponding approximate measurement, where appropriate, modified by "about").

All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context.

The use of the terms "a" and "an" and "the" and similar referents in the context of describing the invention are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Thus, "a" and "an" as well as "the" may mean at least one, or one or more.

As used herein, the term "and/or" means each individual alternative as well as a combination of alternatives, e.g., "first and/or second barrier" is intended to mean only one barrier, only another barrier, or both first and second barriers.

The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any element as essential to the practice of the invention unless explicitly stated.

In the present description, when "selected from" or "selected from the group consisting of" is used, it also means all possible combinations of the stated and terms, as well as each individual term.

The citation and incorporation of patent documents herein is for convenience only and does not reflect any view of the validity, patentability, and/or enforceability of such patent documents.

Any aspect or embodiment of the invention described herein with respect to one or more elements utilizing terms such as "comprising," "having," "including," or "containing," is intended to provide support for similar aspects or embodiments of the invention ("consisting of," "consisting essentially of," or "including" the particular element or elements) unless stated otherwise or the context clearly contradicts (e.g., a composition described herein as including a particular element should be understood as also describing a composition consisting essentially of that element unless stated otherwise or the context clearly contradicts).

This invention includes all modifications and equivalents of the various aspects presented herein or of the subject matter recited in the claims appended hereto as permitted by applicable law.

The features disclosed in the foregoing description may, both separately and in any combination thereof, be material for realizing the invention in diverse forms thereof.

Experiment of

Example (c): composite filters targeting specific contaminant components

The active particles, as broadly defined, may be physically or chemically attached to the substrate. The physical attachment may be used to trap the active particles between two thin layers of felt or paper or within a compact filament stack, or when the fiber strands are twisted or heat sealed in a small recess between two nylon meshes or between a nylon mesh and a particle composite filter. One chemical attachment may be achieved by adding an adhesive layer that attaches the active particles to the surface of the substrate.

More specifically, the foam-type composite filter shown in fig. 1 may be prepared in a similar manner as described in Oehler et al, U.S. patent No.5,820,927, or by the following description. The foam substrate is coated with a subbing layer that ensures a secure attachment of the active particles. The adhesive bondline may preferably be made of a hot melt adhesive, but polystyrene, ABS, styrene or other adhesives would also be useful.

The synthesis of the composite filter comprises the following steps: the foam is expanded with a suitable solvent, such as Dichloromethane (DCM), and the substrate is coated with glue (e.g. by dissolving a hot melt adhesive stick in DCM). The solvent may be prepared as 50 grams of an ethylene vinyl acetate based adhesive (such as a 3M #3792 hot melt stick) dissolved in 1L of DCM. The solvent should be kept in a closed glass bottle with a lid while stirring and heating until the glue stick dissolves. The solvent temperature should not exceed 35 deg.f. The solvent causes the foam to expand by a factor of, for example, two.

The foam is then placed in a solvent and allowed to expand. Foam expansion increases the pore size in the foam, which increases the foam surface area and thus the activated carbon particle coverage. After about 10 seconds, the foam was removed and shaken to prevent any voids from being plugged with glue. After soaking in a solvent, the foam shrinks. This shrinkage acts to impart optimal bonding between the substrate and the activated carbon particles. The foam was then placed on a metal stand and dried. When the foam is applied multiple times (2 to 10 times, optimally 5 times), the optimum bondline thickness is obtained. When the substrate is placed in a solvent, it is important that the foam only stays in the solvent long enough for the entire foam to contact the solvent, but not so long that the solvent dissolves the formed glue line. After final coating, the foam was placed on a metal stand and the carbon particles were poured onto the "wet" foam. The foam was then turned over and the carbon particles were poured on the other side.

The working time to introduce the carbon is about 0.5 to 1 minute. The activated carbon particles may be activated carbon spheres, activated carbon beads, granular activated carbon particles, or mixtures thereof. The activated carbon particles have a particle size of about 1000m²G to 1700m²The high surface area in g is determined by pores smaller than 1 nm. The foam is now labeled as a composite filter.

The composite filter is dried for 20 to 30 minutes while resting on a vibrating table that ensures maximum packing and removes any excess carbon particles trapped in the composite filter. The vibration table was vibrated at a frequency of 400Hz and a power of 60W. Once the carbon particles are trapped on the surface, the composite filter is placed in an oven at a temperature of 115 to 135 (optimally, 123) for 10 to 25 minutes (optimally, 15 minutes). The viscosity of the bondline decreases at this temperature, allowing the carbon particles to penetrate into the bondline. The correct temperature is extremely important because too high a temperature makes the bondline too viscous and decomposes the substrate, while too low a temperature makes the bondline too hard for the activated carbon particles to penetrate properly. After heating, the composite filter was then placed on a shaking table for 10 minutes or until the composite filter cooled. The reduced viscosity of the vibration of the glue-bonded vibrating table causes the carbon particles to bond more tightly to the glue layer, allowing the glue to penetrate into the surface pores of the activated carbon particles and thus securely trap the activated carbon particles to the substrate.

Flexible knits, mesh bundles, air permeable three dimensional rigid frames (e.g., metal wires or monofilaments), and brush-like composite filters can all be used as the carrier structure for the composite filter media in a similar manner as described for the foam carrier.

To target formaldehyde, the active particles may be a catalyst (such as cerium (IV) oxide (CeO)₂) 1 wt% of doped gold nanoclusters, 1 wt% of Pt/TiO on particles₂Granular, 0.1 wt% Pt/Fe₂O₃Particulate, 3 wt% Pt/MnOx-CeO₂Particles), impregnated acidic activated carbon particles (such as potassium permanganate, 4-aminobenzoic acid (PABA), or hexamethylenediamine (HMD a)), photocatalyst particles (such as titanium dioxide (TiO)₂) Or metal organic framework particles (such as aluminum fumarate, HKUST-1 (copper benzene-1, 3, 5-tricarboxylate), FeBTC (iron 1,3, 5-benzenetricarboxylate), ZIF-8 (zinc 2-methylimidazole salt), or Ni-MOF-74). To target NOx, the active particles may be potassium containing impregnated basic activated carbon particles, such as potassium nitrate (KNO)₃) Potassium hydroxide (KOH), potassium carbonate (K)₂CO₃) Or potassium sulfate (K)₂SO₄). To target VOCs, the active particles may be activated carbon particles that have a high available surface area/capacity to adsorb a large number of molecules and may be non-impregnated activated carbon particles. To target acid gases (such as hydrogen sulfide, sulfur dioxide, nitric acid, sulfuric acid, nitrous acid, hydrochloric acid, formic acid, acetic acid), alkaline treated active particles are required. However, basic gases (such as ammonia, amines, proton acceptors/electron donors) will be more effectively removed by the acidic particles. The active particles targeting sulfur dioxide and hydrogen sulfide may be alkaline impregnated activated carbon particles, such as potassium hydroxide (KOH) or sodium hydroxide (NaOH) or another similar base. To target ammonia gas, the active particles may be activated carbon particles modified to have a large number of oxygen surface groups on the surface layer, such as bronsted acid (such as carboxylic acid groups) or lewis acid sites. The active particles may be acid-impregnated activated carbon particles, such as nitric acid (HNO)₃) Sulfuric acid (H)₂SO₄) Or similar acid treated activated carbon particles.

To remove high concentrations of formaldehyde, NOx, and VOCs, composite filters require at least three different active particles.

1) One example of a composite filter that targets the removal of formaldehyde, NOx, and VOCs may have a ratio between three different active particles as follows: 1 to 35 wt% gold nanoclusters on cerium (IV) oxide, 40 to 95 wt% potassium hydroxide (alkaline/basic) impregnated activated carbon, and 1 to 30 wt% activated carbon particles.

2) Another example of a composite filter targeting the same air pollution may have the following ratio between the three active particles: 1 to 30 wt% of potassium permanganate impregnated activated carbon, 40 to 95 wt% of potassium hydroxide (alkaline/alkaline) impregnated activated carbon, and 1 to 30 wt% of activated carbon particles.

All wt% are wt% of the active particles. Sulfur species such as hydrogen sulfide and sulfur dioxide are very reactive with metal centers and are therefore known to poison catalysts. One way to overcome this problem is to have composite filters with differential active particle ratios, or one particle ratio on a first half of the composite filter and another particle ratio on the other half, where the fraction of a given particle type varies with depth from the front to the back of the composite filter. The upstream particle ratio may then have a large number of active particles that target sulfur compounds. These active particles will remove the sulfur compounds and thereby protect the catalyst from poisoning. Then, the downstream side of the composite filter may have an active particle concentration in which the fraction of catalyst particles increases.

3) One example of a composite filter that will overcome the problem of catalyst poisoning may have the following ratio on the upstream side of the composite filter: 45 to 95 wt% potassium hydroxide (alkaline/basic) impregnated activated carbon, 5 to 40 wt% acidic activated particles, and 5 to 30 wt% activated carbon particles. Then, the downstream side of the composite filter may have the following ratio: 50 to 60 wt% gold nanoclusters on cerium (IV) oxide, 20 to 60 wt% potassium hydroxide (alkaline/basic) impregnated activated carbon, 1 to 20 wt% acidic activated particles, and 1 to 20 wt% activated carbon particles.

Another example of a composite filter is a composite filter designed to remove ammonia.

4) One example of a composite filter that targets NOx, formaldehyde, VOCs, and ammonia can have the following active particulate ratios: 1 to 30 wt% of gold nanoclusters on cerium (IV) oxide, 40 to 95 wt% of potassium hydroxide (alkali/alkaline) impregnated activated carbon, 1 to 30 wt% of activated carbon, and 1 to 15 wt% of nitric acid or sulfuric acid impregnated activated carbon.

Claims

1. A composite filter for removing a plurality of target molecules from a gas stream, comprising a three-dimensional porous support that is permeable to the gas stream, a first plurality of active particles for removing a first target molecule, and a second plurality of active particles for removing a second target molecule, wherein the first plurality of active particles is different from the second plurality of active particles, wherein the first and second plurality of active particles are immobilized in or by the support, and wherein the first and second plurality of active particles are each independently selected from the group consisting of: activated carbon particles, activated carbon particles pretreated/impregnated with a metal, activated carbon particles pretreated/impregnated with an enzyme, activated carbon particles pretreated/impregnated with a basic compound, activated carbon particles pretreated/impregnated with an acidic compound, Metal Organic Framework (MOF) particles, catalyst particles, doped metal oxide particles, 1 wt% Pt/TiO₂Granular, 0.1 wt% Pt/Fe₂O₃Particulate, 3 wt% Pt/MnOx-CeO₂Particles, photocatalytic particles.

2. The composite filter of claim 1, wherein the first plurality of active particles are selected from doped metal oxide particles and the second plurality of active particles are selected from impregnated activated carbon particles.

3. The composite filter of claim 2, wherein the doped metal oxide particles are doped to provide chemical properties that target specific moieties of contaminants, such as gold nanoclusters on modified graphene or other metal nanoclusters, such as silver nanoclusters, e.g. cerium(IV) oxide (CeO)₂) 1 wt% gold on the particles.

4. The composite filter of claim 1, wherein the first plurality of active particles are selected from metal-organic framework particles, such as at least one of aluminum fumarate, HKUST-1, FeBTC, ZIF-8 or Ni-MOF-74, Cu-BTC.

5. The composite filter of claim 2 or 3, wherein the second plurality of active particles are selected from metal-organic framework particles, such as at least one of aluminum fumarate, HKUST-1, FeBTC, ZIF-8 or Ni-MOF-74, Cu-BTC.

6. The composite filter of claim 1, wherein the first and/or second plurality of active particles are doped to provide a chemistry that targets a contaminant of a particular moiety.

7. The composite filter of any of the preceding claims, wherein the porous support comprises a third plurality of active particles for removing a third target molecule, wherein the third plurality of active particles is different from the first and second plurality of active particles, and wherein the third plurality of active particles is immobilized in or by the solid support.

8. The composite filter of any one of the preceding claims, wherein the porous carrier body comprises a further plurality of active particles for removing a further target molecule, wherein the further plurality of active particles is different from the first, second and third plurality of active particles, and wherein the further plurality of active particles is immobilized in or by the solid carrier.

9. The composite filter of any of the preceding claims 7 and 8, wherein the first plurality of active particles, second plurality of active particles, and second plurality of active particlesThe plurality of active particles, the third plurality of active particles and optionally the further plurality of active particles are each independently selected from the group consisting of activated carbon particles, activated carbon particles pre-treated/impregnated with a metal, activated carbon particles pre-treated/impregnated with an enzyme, activated carbon particles pre-treated/impregnated with a basic compound, activated carbon particles pre-treated/impregnated with an acidic compound, Metal Organic Framework (MOF) particles, catalyst particles, doped metal oxide particles, 1 wt% Pt/TiO particles₂Granular, 0.1 wt% Pt/Fe₂O₃Particulate, 3 wt% Pt/MnOx-CeO₂Particles, photocatalytic particles; with the proviso that the first plurality of active particles, the second plurality of active particles, the optional third plurality of active particles, and the optional further plurality of active particles are selected from different active particles.

10. The composite filter according to any one of the preceding claims, wherein the three-dimensional porous support is selected from the group comprising: (i) a foam support body having a reticulated pore structure, (ii) a felt of chemical or biopolymer fibers, (iii) stranded fiber strands, (iv) a flexible knit, (v) a mesh bundle, (vi) a wire pack, (vii) a pleated paper substrate, (viii) an air permeable three-dimensional rigid frame (e.g., a metal wire or monofilament), (viii) a brush filter, and (ix) a material designed to impart a reaction surface of minimum flow resistance and maximum accessibility to gas flow.

11. The composite filter of any one of the previous claims, wherein the pore size is 25PPI, or more accurately 5PPI to 20 PPI.

12. The composite filter of any of the preceding claims, wherein the first, second, optional third, and optional further plurality of active particles have an average particle size of from 100m²G to 7000m²Total surface area in g.

13. The composite filter of claim 12, which isWherein the first plurality of active particles, the second plurality of active particles, the optional third plurality of active particles, and the optional further plurality of active particles have a particle size of from 800m²G to 2000m²Total surface area in g.

14. The composite filter of any of the preceding claims, wherein the first plurality of active particles, second plurality of active particles, optional third plurality of active particles, and optional further plurality of active particles are secured to the pore structure of the carrier by an adhesive forming an adhesive layer.

15. The composite filter according to any of the preceding claims, wherein the first or second plurality of active particles are selected from activated carbon particles, such as activated carbon spheres, activated carbon beads, and/or activated carbon granules.

16. The composite filter of any of the preceding claims, wherein the first, second, optional third, and optional further plurality of active particles have an average particle size in a range from 0.005mm to 3.0 mm.

17. The composite filter of any of the preceding claims, wherein the first plurality of active particles, second plurality of active particles, optional third plurality of active particles, and optional further plurality of active particles are independently selected from activated carbon particles pretreated with lithium permanganate, calcium acetate, copper dioxide, potassium hydroxide, potassium permanganate, manganese dioxide, copper nitrate, manganese acetate, potassium carbonate, or sodium permanganate.

18. The composite filter of any of the previous claims, wherein the foam is a polyurethane-based foam.

19. The composite filter of any of the preceding claims, wherein the adhesive layer has a thickness obtainable by coating the foam at least twice with the adhesive.

20. The composite filter according to any of the preceding claims, wherein the adhesive is selected from a hot melt adhesive, or an adhesive based on polystyrene, urethane, liquid resin, polyurethane and/or styrene.

21. Use of a composite filter according to any of claims 1 to 20 in an air cleaning device.

22. Use of a composite filter according to any one of claims 1 to 20 in an air conditioning unit.

23. An air cleaning device comprising a composite filter according to any one of claims 1 to 20.

24. A motor vehicle comprising an air conditioning device, an air cleaning device, or both an air cleaning device and an air conditioning device, wherein any of the devices comprises a composite filter according to any of claims 1 to 20.

25. A method of removing contaminant molecules from ambient air, the method comprising conveying the ambient air through a composite filter according to any one of claims 1 to 20.